In an Arabic language Bible, Allah is what you would find where an English language Bible would have God.

My understanding is that Mohammed always said that the religion he was preaching was the same religion as that of Abraham and Isaac and so forth. And also the same as that of Jesus. Essentially he saw his mission as one of reformation and completion of a religious project that he believed had gone astray into Jewish tribalism, and Christian superstition.

I'm sure that many Muslims prefer to use the term Allah, because for them it is important to give a special place to the Arabic language. But their central belief is that there is no God but Allah.